Giant squid among creatures of the deep hiding off WA’s Ningaloo Coast, research reveals

Western Australia’s famed Ningaloo Coast is hiding secrets in deep underwater canyons, with researchers discovering species previously unknown to the area in their depths, and others thought to be entirely new to science.

Researchers surveyed the Cape Range and Cloates submarine canyons, about 1200 kilometres north of Perth, collecting more than 1000 samples from the surface all the way down to the sea floor more than 4500 metres below.

Using environmental DNA (eDNA) – genetic material naturally shed by animals into seawater – scientists on the expedition, led by the WA Museum on board the Schmidt Ocean Institute’s R/V Falkor, were able to document what lurked in the deep sea without needing to see or capture the creatures.

Among the most striking finds were traces of the giant squid, detected across six separate samples, plus deep-diving whales such as the Pygmy sperm whale and Cuvier’s beaked whale.

Giant squid typically grow to between 10 and 13 metres in length – longer than a school bus – can weigh up to 275 kilograms, and have the biggest eyes in the animal kingdom, comparable to the size of a large pizza.

The elusive animals, which sparked stories of the mythological kraken monster, have rarely been seen by scientists in person, making the use of eDNA in studying them even more critical.

The study detected 226 species in total across 11 major animal groups, including rare fish, cnidarians, echinoderms, squid, marine mammals and more.

Dozens of those species had never previously been recorded in WA waters, including the sleeper shark, faceless cusk eel and the slender snaggletooth.

Lead author Dr Georgia Nester, who conducted the research as part of her PhD, said the results highlighted how little was known about WA’s deep-sea ecosystems.

“Finding evidence of a giant squid really captures people’s imagination, but it’s just one part of a much bigger picture,” she said.

“We found a large number of species that don’t neatly match anything currently recorded, which doesn’t automatically mean they’re new to science, but it strongly suggests there is a vast amount of deep-sea biodiversity we’re only just beginning to uncover.”

Nester collected water samples and combined eDNA analysis with genetic reference sequences from physical specimens collected by a remotely operated vehicle.

She said eDNA allowed the team to detect fragile, rare and fast-moving species that traditional cameras and nets may miss.

“These canyons are incredibly rich ecosystems and, until now, they’ve been largely unexplored because of the difficulty of working at such extreme depths,” Nester said.

“With eDNA, a single water sample can tell us about hundreds of species at once.

“That means we can dramatically expand our understanding of deep-water environments in a way that simply hasn’t been possible before.”

“This is the first record of a giant squid detected off Western Australia’s coast using eDNA protocols and the northernmost record of them in the eastern Indian Ocean.”

Dr Lisa Kirkendale

Senior author, associate professor Zoe Richards, said eDNA had the potential to transform how scientists explore and protect the ocean.

“Deep-sea ecosystems are vast, remote and expensive to study, yet they face growing pressure from climate change, fishing and resource extraction,” she said.

“Environmental DNA gives us a scalable, non-invasive way to build baseline knowledge of what lives there, which is essential for informed management and conservation.

“You can’t protect what you don’t know exists.”

The physical specimens were identified by taxonomists and are now permanently housed in the WA Museum’s collection and research facility to aid further taxonomic research.

WA Museum head of aquatic zoology and curator of molluscs Dr Lisa Kirkendale said there were only two other records of the giant squid in WA, but there had not been a sighting or a specimen for more than 25 years.

“This is the first record of a giant squid detected off Western Australia’s coast using eDNA protocols and the northernmost record of them in the eastern Indian Ocean,” she said.

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